Gas turbine engines are well known internal combustion engines typically used to provide thrust to an aircraft or to provide power for land-based operations. Generally speaking, a gas turbine engine includes a fan, a compressor, a combustor and a turbine arranged in a serial fashion along a longitudinal axis of an engine. The fan draws in ambient air as it rotates and moves it to the compressor where the air is compressed or pressurized. The compressed air is then communicated to the combustor where it is mixed with fuel and ignited. The products of the combustion are hot gases which are then directed into the turbine. This causes the airfoils in the turbine to rotate, and as the turbine is mounted on the same shaft, or shafts, as the compressor and fan, this causes the compressor and fan to rotate too. Accordingly, once started, it can be seen that the operation of the engine is self-sustaining in that the combustion of more fuel with air causes more rotation of the turbine and in turn the compressor and the fan. Moreover, the rotation of the fan, which typically has a diameter many times that of the compressor and the turbine, causes the engine to generate thrust.
In order to increase operational efficiency, and thereby decrease fuel consumption, new gas turbine engine designs require a diffuser-combustor assembly to further include a pre-diffuser that is positioned between an exit of the high-pressure compressor and the entrance to the combustor. One means to provide such a pre-diffuser is to create a strut that extends between an inner-ring and an outer-ring of an inner casing of the diffuser-combustor assembly.
However, such a strut design is not without problem since such a strut is positioned in the flowpath of the hot, compressed air that exits the high-pressure compressor. As such, the temperature of the hot, compressed air exiting the compressor may not be equal along an axis extending between the inner and outer-ring of the inner casing, and thus also along a radial axis of the strut that extends between the inner-ring and outer-ring of the inner casing. Thus, the strut may experience a differing expansion or contraction rate than the inner and outer-rings. Thus, a need exists to counteract such ring-strut-ring thermal fighting of a strut pre-diffuser design.